Sizing Tailwater Recovery Systems to Utilize Runoff From Precipitation on Irrigated Lands.

摘要

Runoff from precipitation on furrow irrigated land is considered as an alternative source of irrigation water in Western Kansas. This helps to prolong the life of ground water supplies. A continuous watershed simulation model was used to estimate the amount of runoff generated from field-size furrow irrigated areas. The runoff was then routed through various sizes of tailwater recovery pits to determine the amounts of runoff utilized,based on continuous pumping systems. Pit size is the main factor affecting the percentage of runoff utilized. When the storage volume of the pit increases to 5times the normal tailwater recovery pit size,about 70percent of the runoff from precipitation was utilized. The quantity of ground water used decreases as the quantity of runoff utilized increases. Both of these terms can be expressed in a second-order polynomial equation. The sum of all the costs affected by the use of runoff from precipitation determines the optimum pit size. The factors which determine the optimum pit size are quantity of runoff available to be utilized,pumping lifts of well and pit,type of fuel used,and fuel price. If the fuel price and well pumping lift rise above a certain level,it might become economically feasible to construct a larger pit to utilize runoff from irrigated land.